V. F. Lukichev

Photovoltaic effect in a structure based on amorphous and nanoporous silicon formed by plasma immersion ion implantation

A p-i-n structure with photovoltaic properties was proposed and fabricated by plasma immersion ion implantation. Implantation of helium ions with an energy of 1 to 5 keV with subsequent annealing creates a region of nanoporous silicon at a depth of ∼20 to 80 nm from the silicon substrate surface. A nanocrystalline structure of this layer results in high light absorption and a change in the band-gap energy, which leads to the formation of a heterojunction. The upper layer of the modified region was additionally doped with boron to create a p region. The resulting structure showed a photovoltaic effect (0.15 V, 6.4 mA/cm2) under illumination with light equivalent to sunlight in terms of the spectral range and intensity.

Optimization of the tomographic algorithm of the reconstruction of plasma irregularities in process reactors of microelectronics

In this article, an algorithm of two-aspect emission optical tomography of plasma taking into account apriori data about the object of investigation is developed. The reconstruction algorithm was tested for statistically large number of phantoms. The cases of incorrect operation of the suggested algorithm were revealed and the methods of its improvement were suggested. The improved algorithm of emission optical tomography compatible with industrial plasmochemical reactors of low-temperature plasma allows us to reconstruct a two-dimensional distribution of plasma particles with the reconstruction error lower than 15% for 90% of randomly selected phantoms.

Emission tomography of plasma in technological reactors of microelectronics

Optical emission tomography is a promising method for the analysis of the lateral distribution of the particle density in plasma of plasma-chemical reactors, which is very critical in technological processes of microelectronics on large-diameter wafers. In this work, we propose an algorithm of the tomographic reconstruction of the 2D distribution of plasma components in the cross section of the reactor by their spectrally allowed optical emission at an extremely small number of recording angles. The geometry of the collection of the tomographic data was selected so that it would be compatible with the existing industrial types of plasma reactors. The algorithm is tested for artificially created phantoms in a physical model experiment and is applied to an actual plasma chemical reactor.

Modeling of quantum noise and the quality of hardware components of quantum computers

In the present paper methods and algorithms of modeling quantum operations for quantum computer integrated circuits design are developed. The results of modeling of practically important quantum gates: controlled-NOT (CNOT), and controlled Z-transform (CZ) subject to different decoherence mechanisms are presented. These mechanisms include analysis of depolarizing quantum noise and processes of amplitude and phase relaxation.

Simulation of the effects of deep grooving in silicon in the plasmochemical cyclic process

The results of computer simulation of the effects of the formation of deep groove profiles in silicon during the cyclic etching-passivating process in SF6/C4F8 plasma are reported. It is shown that the groove profile varies under variations in one of the basic parameters of the process, the etching-passivation time ratio at different probabilities of the reactions of etching and the deposition of a fluorocarbon film. The sensitivity of the model to these parameters is determined. Grooves with different tilt angles of walls are simulated, and the opportunity for controlling the groove profile by varying the parameters during grooving is shown.

Study of higher order correlation functions and photon statistics using multiphoton-subtracted states and quadrature measurements

The estimation of high order correlation function values is an important problem in the field of quantum computation. We show that the problem can be reduced to preparation and measurement of optical quantum states resulting after annihilation of a set number of quanta from the original beam. We apply this approach to explore various photon bunching regimes in optical states with gamma-compounded Poisson photon number statistics. We prepare and perform measurement of the thermal quantum state as well as states produced by subtracting one to ten photons from it. Maximum likelihood estimation is employed for parameter estimation. The goal of this research is the development of highly accurate procedures for generation and quality control of optical quantum states.

Investigating the effect of amplitude and phase relaxation on the quality of quantum information technologies

In the formalism of quantum operations, we investigate the effect of the amplitude and phase relaxation on the evolution of quantum states. A model of the polarizing qubit, whose noises depend on the spectral degree of freedom that manifests itself in the process of light propagation in the anisotropic medium with dispersion, is discussed. An approximate analytical model is proposed for evaluating the effect of the phase plate on the polarizing state, taking into account the dispersion of light.

Quantum noise and the quality control of hardware components of quantum computers based on superconducting phase qubits

A general approach to the provision of the quality and efficiency of quantum information technologies is proposed. The approach is based on the analysis of quantum noise generated on the implementation of quantum operations. The method of precision quantum measurements of logic quantum gates based on superconducting phase qubits is developed. The universal method of quantum state and process tomography is used to carry out a comprehensive analysis of the fidelity of the tomography of two-qubit SQiSW, CNOT, and CZ gates arising from the capacitive coupling between qubits. The method of optimization of quantum process tomography is proposed to provide a substantially higher degree of adequacy and fidelity compared to those attained by previously known methods. The examples of simulation of depolarizing quantum noise and amplitude- and phase-relaxation processes on the implementation of quantum operations in registers are considered.

Boron Profile Sharpening in Ultra‐Shallow p+‐n Junction Produced by Plasma Immersion Ion Implantation from BF3 Plasma

We have investigated plasma immersion ion implantation (PI3) of boron with energies of 500 eV (doses up to 2×1015 cm−2) from BF3 plasma with He pre‐amorphizing implantation (PAI) (energy 3 keV, dose 5×1016 cm−2). Implanted samples were subjected to RTA (T = 900 to 1050 °C, t = 2 to 24 sec and spike anneal). SIMS analysis of boron profiles revealed its anomalous behavior. For short RTA times the profile tail (below 5×1019 cm−3) moves toward the surface and then, as in the usual diffusion, toward the bulk at longer annealing times.

Quantum states tomography with noisy measurement channels

We consider realistic measurement systems, where measurements are accompanied by decoherence processes. The aim of this work is the construction of methods and algorithms for precise quantum measurements with fidelity close to the fundamental limit. In the present work the notions of ideal and non-ideal quantum measurements are strictly formalized. It is shown that non-ideal quantum measurements could be represented as a mixture of ideal measurements. Based on root approach the quantum state reconstruction method is developed. Informational accuracy theory of non-ideal quantum measurements is proposed. The monitoring of the amount of information about the quantum state parameters is examined, including the analysis of the information degradation under the noise influence. The study of achievable fidelity in non-ideal quantum measurements is performed. The results of simulation of fidelity characteristics of a wide class of quantum protocols based on polyhedrons geometry with high level of symmetry are presented. The impact of different decoherence mechanisms, including qubit amplitude and phase relaxation, bit-flip and phase-flip, is considered.